The invention relates to a housing for opto-electronic components with a cooler.
Many electronic components, particularly opto-electronic components, must be cooled to temperatures far below the ambient temperature in order to achieve their operating temperature or to reduce the thermal agitation noise, and placed in a Dewar vessel for heat insulation from the atmosphere.
Rapid cooling of the component in less than 2 s is often required in order for it to reach its operating temperature, while the cooling effect and so the operating capacity of the component is only to be maintained for a short time. For such purposes, Joule-Thomson coolers are used as a rule, in addition to Stirling or Peltier coolers, and achieve a temperature reduction of the gas by adiabatic expansion of a gas compressed to 100-300 bars.
With the aid of the countercurrent principle, the highly compressed gas flowing in from a high-pressure gas reservoir or from a compressor is pre-cooled before its expansion by the expanded gas flowing back in a heat exchanger pipe of the Joule-Thomson cooler that separates two media with differing temperatures.
By combined application of the process steps temperature reduction by adiabatic expansion and pre-cooling of the compressed gas in the heat exchanger, liquefaction of the cooling medium, e.g. nitrogen or argon gas, can be achieved. The operating temperature of the component then corresponds to the respective liquefaction temperature of the cooling medium used.
For cooling opto-electronic components with Joule-Thomson coolers, embodiments are known in which the entire Joule-Thomson cooler in the conventional design is inserted in a tightly fitting and completely separable housing, which comprises a glass inside wall and a metal outside wall for heat insulation.
The heat exchanger pipe of the Joule-Thomson cooler is wound in coiled form around a cylindrical or conical metallic support element and then soldered on. In addition, metal ribs can be soldered onto the outside of the heat exchanger pipe to increase the effective surface of the heat exchanger. The component to be cooled is inside the completely separable housing near to the end of the Joule-Thomson cooler at the level of the expansion nozzle, since the temperature is lowest there and so the cooling action is most effective. To prevent the upper side of the component icing up due to gas condensation and thereby rendering the component unserviceable, the Dewar vessel enclosing the Joule-Thomson cooler is evacuated.
To achieve a good cooling action, a Joule-Thomson cooler must have good insulation from the cold to the warm end both in the radial direction and along the support element. This is achieved in the prior art by the metallic support element for the heat exchanger pipe being designed with very thin walls because of the good heat conductivity of the metal.
The drawback here, however, is that due to the low strength of the thin-walled metal support element, stability problems occur. In addition, high production expenditure is needed since the support element is electro-deposited as a shaped part, the heat exchanger pipe is first wound onto the support element and then soldered, and the Joule-Thomson cooler must additionally be inserted into a very close-fitting housing for insulation purposes.